Method game_over

rl/tic_tac_toe.py:176–221

(self, force_recalculate=False)

    return h

  def game_over(self, force_recalculate=False):
    # returns true if game over (a player has won or it's a draw)
    # otherwise returns false
    # also sets 'winner' instance variable and 'ended' instance variable
    if not force_recalculate and self.ended:
      return self.ended
    
    # check rows
    for i in range(LENGTH):
      for player in (self.x, self.o):
        if self.board[i].sum() == player*LENGTH:
          self.winner = player
          self.ended = True
          return True

    # check columns
    for j in range(LENGTH):
      for player in (self.x, self.o):
        if self.board[:,j].sum() == player*LENGTH:
          self.winner = player
          self.ended = True
          return True

    # check diagonals
    for player in (self.x, self.o):
      # top-left -> bottom-right diagonal
      if self.board.trace() == player*LENGTH:
        self.winner = player
        self.ended = True
        return True
      # top-right -> bottom-left diagonal
      if np.fliplr(self.board).trace() == player*LENGTH:
        self.winner = player
        self.ended = True
        return True

    # check if draw
    if np.all((self.board == 0) == False):
      # winner stays None
      self.winner = None
      self.ended = True
      return True

    # game is not over
    self.winner = None
    return False

  def is_draw(self):
    return self.ended and self.winner is None